Roaming may refer to the extension of connectivity service in a location that is different from the home location where the service was registered. In legacy roaming, i.e. conventional roaming, all session keys are generated in a home network and transferred to a visited network. The visited network may then authenticate a mobile station subscriber, and generate charging records in order to charge the subscriber for using the visited network. The possibility to roam and the choice of roaming network operator, namely, the visited network, may be a decision of the home network operator only. The ability for a mobile station subscriber to set up a roaming connection directly with the visited network without having to use the home network as an intermediary may be desirable.